Apple snails are easy animals that do well in a common aquarium or a pond.
They can live together with most fish species and they can be used to keep the
aquarium clean of algae. Not all apple snail species are a good choice for aquaria
as their voracious appetite for aquatic vegetation is often not desired and
the bigger species can cause problems with
the water quality in smaller tanks.
The purpose of this guide is to provide a solid guide for everyone keeping these
snails and to avoid the most common misconceptions and pitfalls.

Species specific needs
Most apple snails are voracious plant eaters (herbivores or macrophytophagous)
that eat a wide range of vegetation. Held
in captivity, they do well on common vegetables in combination with fish food.
Unfortunately, many species have a great appetite for aquatic vegetation and
algae are not their preferred food. In such cases these scavengers can reduce
the aquatic vegetation very quickly. They can ruin a beautiful aquarium within
days.

Algea on the glass of an aquarium with teeth marks
of apple snails (Marisa cornuarietis).

However not every apple snail deploys the same appetite, it mainly depends
on the species of apple snail. So in this way,
it could be useful to know which snail species has been released in the aquarium.
It should be emphasised in this context that the identification of apple snails
is difficult. The difficulty to determine the species lies herein that many
apple snail species are very similar in appearance. A basic identification guide
for apple snails is available in the species section.
It would be a nice thing if the apple snail names were applied correctly, but
the most commonly used names: mystery snails, golden apple snail, ivory snails
and so on are used for many of the apple snail species and most aquarium shops
aren't even aware of the different species at all.
The colours of the apple snail aren't useful to determine the species as many
variations occur within a single species. Examples of this can be seen at the
Pomacea canaliculata section and the
Pomacea diffusa section.
A better approach is the shell shape, but even
that can be tricky and is only useful for certain species. Luckily, only a few
species are common in the aquarium trade, which simplifies the whole matter.
So I'll describe only the needs for these specific species. If you don't manage
to find out which species you have then it's a good idea to try if they eat
your plants before putting several of these creatures in your aquarium.

The teeth
of an apple snail reside on the rasp-like tongue, which is pulled out
and retracted to gather food.
(Pomacea canaliculata).
(click on picture for large version)

Pomacea diffusa
(spike-topped apple snail, Brazilian apple snail, golden mystery snail and ivory
snail) prefers dead and rotting plants above fresh green ones. Occasionally
they eat the softer vegetation. Pomacea
diffusa snails are thus a good choice for an aquarium equipped
with a nice collection of water-plants. What is even more: they tend to starve
to dead in the middle of the vegetation if you don't provide them with enough
food.
The Pomacea diffusa apple snails do very well on all kind of fish food
and it could be useful to try some soft vegetables for those cases they would
like some green food. Very handy types of fish-food are those tablets sold for
algae-eaters, but other types of fish-food will do as well. If you like to keep
the expenses low, just buy pond-fish food. This comes in a big quantity for
a relatively low price and has a big advantage: it keeps floating, so it won't
make a mess on the bottom of your aquarium and the left-over can be removed
easily. Although floating food might seems a bit strange for snails, apple snails
know very well how to handle it: they go to the surface and form a funnel with
their foot in which they let the water from the surface flow through (ciliary
feeding, as can be seen in ecology section and in the anatomy section). The food at the surface
then floats towards the snail and gets stuck in this funnel after which the
snail eats the catch.

Important: Always thoroughly wash the vegetables if you're not sure that they
are come from a biological farm. Vegetables should be free of insecticides and
molluscides and it won't hurt to play safe. You probably won't feel anything
when you eat vegetables with some residues of these products on it, but the
snails could be harmed!

Other types of food
Besides vegetables and fish food pellets, apple snails also eat all kinds of
other food if available. Apple snails won't refuse brine shrimps and other frozen
foods or even dead fish and insects. Even other snails can appear on the menu
of an apple snail (this has been reported for Pomacea canaliculata
and Marisa cornuarietis).
This makes them also a good option for tank cleaning.
Apple snails do eat microscopic vegetation (micropagous) that grows on stones,
the wall of the tank etc., but don't expect them to 'clean' the tank completely
from algea.
If you want your snails to get out of the water, just attach some food partly
above the waterline. It's partly because of this behaviour (leaving of the water
getting their food) which makes them such a problem in the rice-fields of Asia
and Hawaii, where they feed on the young rice-crops.

How much food?
This a merely a trial-and-error option: just see how much they eat
on a daily base and supply them with that amount every day. This would be a
useful approach if it wasn't that many apple snail species tend to aestivate
(have a dry-time hibernation) or start to hibernate (domancy during the winter
season). The latter situation is the most common form of inactivity in apple
snails that are kept in captivity. During this inactivity period, the amount
of food they need decreases, while in spring and summer the amount of energy
needed increases, when they become active and starts with their reproductional
efforts (egg-production).
These seasonal differences in activity levels are mainly induced by temperature,
which also means that this seasonal variation decreases, but does not necessarily
disappears, when the temperature is kept constant throughout the year.
A better feeding approach would thus be to vary the amount of food: less food
in fall and winter, while increasing the amount to ad libidum (food as much
as they can eat) in spring and summer.

Housing

Water

Apple snails that are found in the aquarium trade don't make high demands when
it comes to water quality: they can live very well in clear, streaming, oxygen-rich
water as well in still water, with rotting organic waste, containing almost
no oxygen.
In general one should apply the same rules for water quality as with fish (ammonia,
nitrite, nitrate etc) and the water should not be too soft. Like most snails,
apple snails prefer calcium rich water. If the calcium concentration in the
water isn't high enough (soft water), they aren't able to build a strong shell and become susceptible to shell damage, but
even in good conditions, some snails still get little holes in the shell surface,
especially in the older parts of their shell. This is a naturally occurring
process and as long it's only at the surface, you shouldn't worry too much about
it. In the 'snail disease' section,
you can see an example of a snail with a damaged shell. Young and healthy snails
are somewhat protected against this as the outer
layer of the shell consist of a protein layer that prevents a breakdown
of the shell, but damaged shells and shells of older snails are quite vulnerable
to shell detoriation.Warning! If the tap-water in your area contains copper and/or other metals,
use one of these water preparation products that catch away those metals bofere
putting the snail in the water. Apple snails are very sensitive for these compounds
(especially copper). You won't be the first one loosing a snail due to this
snail-toxic substances in the water. If you see that the snails become completely
inactive or if the snails, especially the little ones, try to leave the water
after a water change: get a product to treat the water (like aquasafe or for
those with access to a lab: use EDTA or something similar).
When there are many apple snails in a tank, the water tends to become cloudy
because apple snails have a large amount of microorganisms in their intestine,
which help to digest the food, and which are expelled with the faeces. These
micro-organisms (amoebocytes) should not cause any harm to the fish and can
even serve as a food source for young fish. Fresh food (lettuce etc.) are more
likely to induce this micro-organism based clouding of the water. If the snails
are fed with dry fish food, the water will stay cleaner. It is a good idea to
do regular water changes if you have many creatures in one tank, just like one
would advise with fish, to maintain good water quality and to avoid accumulation
of toxic substances and waste. By the way, apple snails are good indicators
for the oxygen-level in your tank. When there isn't much oxygen in the water,
the snails will regularly come to the surface to inhale fresh air through the
breathing siphon. Only when there
is enough oxygen for them in the water, they don't need their lung and solely depend on their gill.

The amount of water needed for each snail depends on the size of the snail,
the filtration capacity and the temperature. As a general rule of thumb one
should provide at least 10-liters/2.5 gallon for each mid-sized snail (±5cm/2inch.
diameter). Or another way: count each apple snail as a fish of the same length
as the snail's shell diameter. Be cautious not to overcrow your snail tank.
While it hasn't been proven that apple snails actually 'sense' that they are
in large numbers in a small space, the water quality quickly detoriates and
substances that inhibit the snail growth are increasing quiker. Regular refreshment
of a part of the water is highly recommended.
The water doesn't have to be deep (2 or more times the shell height). Remember
that most apple snail species inhabit swamps in which the water level is quite
low. Be sure to have a coverplate on your aquarium
or at least make sure that they can't get out of it or otherwise: don't be surprised
to find a snail on the ground in the morning. Don't worry, they can easily survive
out of the water for more then a week, but they risk damaging their shell
when hitting the ground.
An important thing, often forgotten, is to provide an air space above the water
to allow the snail to leave the water to deposit her eggs. This air space should
be at least the same height as the size of the shell. If the snail does not
have access to sufficient air space, the animal will have to deposit the eggs
below the water, where they will drown. Obvious, this does not count for those
species that deposit the eggs below the surface like the giant ramshorn (Marisa
cornuarietis), Asolene
spixi, Lanistes species and others.
Note!: Some species are more likely to creep
out of the water than other species do.
As apple snails prefer to hide themselves in darker places during daytime, some
stones, a trunk or some plants are well appreciated. They also have the habit
of burying in the substrate in search for food and when they aestivate in the
winter periods. If the soil on the bottom is thick and soft the snails can be
hard to locate.

Apple snails are most active during the night, which already indicates their
preference for the darker places of their environment. During the day, they
remain mostly in the shadow of plants and creep away in the bottom and/or mud.
When the dark comes in, the apple snail becomes more active and crawls around
in search for food, a mating partner or a good place to deposit
eggs.
Keep in mind that there is a large variation in activity levels amongst the
different apple snail species. For example Pomacea canaliculata,
the common channeled apple snail or better known as the Golden apple snail (incorrect!
'Golden' should only be used for yellow Pomacea diffusa
snails), is relatively active during the day and often risides close to the
water surface. Pomacea flagellata,
the Mexican or Maya apple snail, hides in the bottom during the day. The well
known Pomacea diffusa (mystery
snail, spiketopped apple snail, golden apple snail) fits in between of these
two activity levels.
Apple snails don't need artificial illumination like TL-tubes, but as you probably
want to observe them, a standard aquarium light-lid would suffice.
If you keep the snails in sunlight, like happens with an outside pond, the shell
of the snails become covered with algae, giving them a green and hairy look.
This might look scary, but it's harmless for the snails.
Suggestion: If you would like to raise baby apple snails,
it would be a good idea to provide enough light, so that some algae can grow
in the aquarium. Little apple snails have a better chance to survive the delicate
first weeks after hatching if they have access to algae as food source.
Light dependent growth has been observed by Pomacea glauca.
If the snails were kept in a completely dark environment, their growth decreased,
compared with animals that were kept in a 12 hour/day light environment. (Zischke
et al. 1970)

Temperature

The optimal water temperature for apple snails lays between 18 to 28°C (65-82°F).
As with many cold-blooded animals, apple snails are more active at higher temperatures.
At higher temperatures, they eat faster, creep faster and they grow faster.
Also higher temperatures mainly induce the reproduction of the apple snail.
At lower temperatures (18°C/65°F) the apple snail enters a dormancy state in
which they creep away in the mud and become very inactive. Temperatures below
18°C/65°F should be avoided as the mortality rate quickly increases.

There are a few things to be considered to successfully breed apple snails:
- Since apple snails are gonochoristic (separated sexes), a male and a female
snail are needed(obvious).
- Apple snails reproduce when the temperature
rises in combination with abundance of food available.
- For those species that lay
their eggs above the water, one should provide enough air space (+15cm/6
inch).
- Some species might need an aestivation period in the mud before they breed
successfully (does not apply to the most common species).

It is also important to mention that female apple snails can store sperm for
months, so even the eggs of a single snail can be fertile. With no male snail
present, female apple snails occasionally produce infertile eggs. Obviously,
these do no hatch. Last but not least: most species lay their eggs above the
water and they should stay there while the eggs of aquatic layers should stay
below the surface.
At the right circumstances an apple snail can produce one clutch of eggs
every 4-7 days during several weeks. After this period, productivity decreases
and the female snail regains strength.
The species, temperature
and availability of food are the main factors in the egg
production.
Read more about the life cycle of apple snails here.

Eggs

Species that lay eggs above the waterline (genera:Pomacea, Asolene
(Pomella) and Pila): After the eggs are deposited, they are soft and
have a rather milky, pink colour. After a few hours, they harden and get their
definitive colour (from pale pink to raspberry-red or even greenish depending
of the species). It might happen that the eggs
at the surface dry out, on which they get a lighter colour.
The size of the eggs varies from 2.2 to 3.5 mm / 0.01 to 0.14 inch each (in
case of Pomacea canaliculata),
whereas Pomacea paludosa and
Pila globosa for example lay eggs
with a diameter of 4 to 7 mm / 0.16 to 0.28 inch. The eggs at the surface probably
won't deliver you many little snails when the air humidity is not optimal, but
often the eggs deeper inside the clutch thrive well.
It's no problem to transfer the egg clutch to another location, as long as you
are careful not cause too much damage. A damages clutch is more prone to infections
and evaporation. The best way to move the eggs is by wetting the clutch, wait
a few hours and then carefully move the clutch over the surface until it comes
off. Obviously this method is of most successful on glass or other smooth surfaces.

It's important to keep the eggs in a moist, but not wet environment. Never
keep these eggs under water (this will drown the embryos)!
Keep the temperature between 18 and 28°C (65-82°F). The higher the temperature,
the faster the snails will hatch.
Note!: Not all apple snails from the genus Pomacea lay their eggs above
the waterline in a clutch. Pomacea urceus
lays about 50 to 200 orange eggs at the inside of the shell near the aperture.
The eggs are brooded in this incubation chamber, closed off with the mother's
operculum (shell-door), while the snail aestivates in the dry mud during the
dry season. The young snails hatch during this period and crawl around under
the female's shell until the rainy season starts. A side effect of this reproduction
method is visible as eggscars on the mother's shell at the place where the eggs
were attached.
In the picture section there are more
pictures of apple snail eggs.

Species that lay their eggs under the waterline
(genera:Asolene (Asolene),
Felipponea,Lanistes
and Marisa):
The eggs are embedded in a transparent gelatinous mass and are relatively small
when they are laid, but take up a lot of water within the first days and swell
significantly (from 3 mm to 6 mm). The need for temperatures between 18 and
28°C (65-82°F) applies to these eggs as well. Obviously these eggs should
stay below the surface!
Interesting in these snails is that one can follow the development of the little
snails inside the eggs (also see the 'embryology'
section).

After 2-4 weeks (depending on the species and the temperature, 14 days at 25°C
in the case of Pomacea canaliculata)
the first little snails should appear. If they don't after 3 weeks, you can
try to help the young snails. It might seem rude, but it works: just break the
clutch in 2 - 3 parts and those in the water. You can even wash the snail out
of the clutch by moving the broken clutch parts through the water. Note that
this isn't neecessary when the moisture of the air is sufficient.
If you don't see little snails after breaking a 4 weeks old clutch, it can be
that the eggs aren't fertilised or that the air moisture was too low. In the
latter case the yolk is very thick or the eggs are completely dried out and
filled with air. You might want to wait until the snails appear on the natural
way (it can take several days before they all are hatched), but keep in mind
that if the clutch isn't kept moist enough, the young snails won't be able to
make their way out and subsequently die.

Young snails

Many young snails might die within the first weeks of their existence, but
those who survive grow quickly. At a size of 2.5 cm /1 inch (2-5 months) in
case of Pomacea canaliculata
and Pomacea diffusa,
they are able to reproduce and the next generation will appear if you don't
remove their eggs in time.
From the day they hatch, the young snails eat the same as their parents, so
there is no need for special babysnail-food. Keep in mind, however, that it's
often difficult for a young snail to obtain enough food in a completely clean
tank. The long distances they need to walk in such case to reach the food could
simply be too much. As a result of this, it's often easier to raise little apple
snails in a tank with algae on the walls so the little snails have enough food
(algae) without traveling all around.
The young apple snails can stay in the same aquarium together with their parents
without being eaten by them as long as there is enough food available. However,
larger fish with preference for (little) snails can be a reason to keep the
young ones in a separated aquarium until they have grown somewhat bigger.
If one plans to transfer the little snail to a separate tank, be sure that their
new environment is already a somewhat stable eco-system. In other words: put
1/3 water from a pond or another aquarium with 2/3 fresh water and let the new
tank stand for 2-3 weeks with vegetation, without other inhabitants before adding
little snails. Such approach certainly increases the success rate with raising
young snails.
And last, but not least: algae and debris might not be appealing to the human
eye, however it's certainly appreciated by the little snails.

Note the red
intestines of these young snails. This is caused by the reddish, carotene-rich
yolk they have lived on when they were growing
inside the eggs. Pomacea diffusa snails
don't have such a red body when they are born (also see the picture above
of hatching Pomacea diffusa snails).

The best way to transport apple snails is put them in a plastic box with moist
synthetic filter cotton or damp paper towels. The snails are better protected
against shell damage during transport this way and as apple snails can stay
out of the water for days to weeks without problems (they are air-breathers
with a shell door), this method is easy and safe. It's important to make some
holes in the lid to provide fresh air when they need to travel for a week or
more. Large apple snails can also be wrapped in newspapers and put in a paper
bag. Transport in a water filled plastic bag is only advised for small snails.
In humid conditions (that you achieve with the method described above), many
species can survive for long periods. For example Marisa cornuarietis
is known to survive for about 120 days out of the water if the humidity is kept
at 80%.

TIP: Have a look at the FAQ to see the most common questions and answers on them.